Aims.As part of the DART project
we have used the ESO/2.2m Wide Field Imager in conjunction with the
VLT/FLAMES GIRAFFE spectrograph to study the detailed properties of the resolved
stellar population of the Fornax dwarf spheroidal galaxy out to and
beyond its tidal radius. Fornax dwarf spheroidal galaxy has had a complicated evolution and contains significant
numbers of young, intermediate age and old stars. We investigate the relation
between these different components by studying their photometric, kinematic and abundance distributions.

Methods.
We re-derived the structural parameters of the Fornax dwarf spheroidal using
our wide field imaging covering the galaxy out to its tidal radius, and analysed the spatial
distribution of the Fornax stars of different ages as selected from
colour–magnitude diagram analysis.
We have obtained accurate velocities and metallicities
from spectra in the Ca II triplet
wavelength region for 562 Red Giant Branch stars which have velocities consistent with
membership of the Fornax dwarf spheroidal.

Results.We have found evidence for the presence of at least three distinct
stellar components: a young population (few 100 Myr old)
concentrated in the centre of the galaxy, visible as a
Main Sequence in the colour–magnitude diagram; an intermediate age
population (2-8 Gyr old); and an ancient population (>10 Gyr),
which are distinguishable from each other kinematically, from the metallicity
distribution and
in the spatial distribution of stars found in the colour–magnitude diagram.

Conclusions.
From our spectroscopic analysis we find that the
“metal rich” stars () show a less extended and more
concentrated spatial distribution, and display colder kinematics
than the “metal poor” stars (). There is tentative evidence
that the ancient stellar population in the centre of Fornax
does not exhibit equilibrium kinematics. This could be a sign of a relatively recent
accretion of external material, such as the merger of another galaxy
or other means of gas accretion at some point in the fairly recent past, consistent
with other recent evidence of substructure (Coleman et al. 2004, AJ, 127, 832; 2005, AJ, 129, 1443).

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